Relax inducing device with heartbeat detection unit

ABSTRACT

A relax inducing device comprises a biological parameter detecting unit for detecting biological parameter of a user, stimulus loading unit for providing a stimulus to the user, relax-level determining unit for determining a relax level of the user by comparing the biological parameter provided from the biological parameter detecting unit with at least one relax-level threshold value, and a stimulus control unit for controlling an amount of the stimulus according to the relax level to induce the user into a relax state. In this device, since an optimum amount of stimulus is provided to the user on a real-time basis, it is possible to efficiently and smoothly induce the user into the relax state.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a relax inducing device for inducing auser to a relax state, and particularly a relax inducing device capableof detecting a biological signal of the user such as heartbeat number orrespiration number, and controlling an amount of stimulus to be appliedto the user according to the biological signal.

2. Disclosure of the Prior Art

In the past, it has been proposed to determine a relax level of a useraccording to a biological signal such as brain wave or heart rate. Forexample, Japanese Patent Early Publication [KOKAI] No. 1-131648discloses to treat values of heartbeat R--R interval defined as a basicperiod of an electrocardiogram of a user by a high-speed Fouriertransform, and determine a relax level index of the user according to apower value of a particular frequency range and a total power value. Inaddition, Japanese Patent Early Publication [KOKAI] No. 3-272745discloses to determine an index by calculating a dispersion of theheartbeat R--R interval. Moreover, Japanese Patent Early Publication[KOKAI] No. 5-42129 discloses to detect a respiration signal in additionto a heartbeat signal of a user, and determine a relax level index bycalculating a dispersion of at least one of those signals. However, whenthe dispersion is used as the relax level index, there is a problem thatthe confidence of the relax level is poor because of individualvariations of the users.

As to a relax inducing device such as a massager of providing a stimulusto a user to induce the user into a relax state, it has been known thatthere are massagers in which a massage motion must be manually adjustedby the user, and a programmed massage motion is provided to the user. Inthe former massager, there is a problem that the adjusting of themassage motion is troublesome. On the other hand, since the latermassager provides the programmed massage motion irrespective of aphysical condition of the user, there is a possibility that the useroften feels the programmed massage motion uncomfortable.

Thus, there is room for further improvement in the method of determiningthe relax level index and the relax inducing device.

SUMMARY OF THE INVENTION

For improving the above problems, the present invention is directed to arelax inducing device capable of controlling an amount of stimulus to beapplied to a user according to a biological parameter of the userchanging moment by moment to induce the user into a relax state. Thatis, the relax inducing device of the present invention comprises abiological-information detecting unit for detecting at least onebiological parameter selected from heartbeat number, respiration number,and brain wave of a user, a stimulus loading unit for providing astimulus to the user, and a stimulus control unit for controlling anamount of the stimulus according to the detected biological parameter toinduced the user into a relax state. The biological-informationdetecting unit detects the biological parameter of the user when theuser utilizes the relax inducing device. The stimulus amount isdetermined according to the detected biological parameter and providedto the user on a real-time basis. Therefore, it is possible toefficiently and smoothly induce the user into the relax state.

It is preferred that the relax inducing device of the present inventioncomprises a relax-level determining unit. The relax-level determiningunit compares the biological parameter provided from thebiological-information detecting unit with at least one relax-levelthreshold value to determine a relax level of the user. In this case,the stimulus control unit controls the stimulus amount according to therelax level.

In addition, it is preferred that the stimulus control unit controls thestimulus amount such that as the biological parameter is smaller, thestimulus amount decreases.

These and still other objects and advantages will become apparent fromthe following description of the preferred embodiments of the inventionwhen taken in conjunction with the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a massage chair, which is an embodimentof a relax inducing device of the present invention;

FIG. 2 is a schematic control diagram of the massage chair of FIG. 1;

FIG. 3 is a graph explaining a control of a massage speed of a massageapplicator in an auto-massage mode of the present massage chair;

FIG. 4 is a flow chart of the auto massage mode of the massage chair;

FIGS. 5A and 5B are detail flow charts of first and second decelerationsections of FIG. 4, respectively;

FIG. 6 is a graph showing a relationship between massage speed of theapplicator and heartbeat number in a six-stage control;

FIG. 7 is a graph showing a relationship between massage speed of theapplicator and heartbeat number in an infinite-stage control;

FIG. 8 is a schematic diagram of a relax-level determining unit;

FIG. 9 is a graph showing a change on time of a relax level of a userobtained by a brain-wave measurement

FIG. 10 is a graph showing a change on time of a change rate of aheartbeat attainment time which is defined as a time period necessary toreach a heartbeat number of 20 times;

FIG. 11 is a graph showing a time lag (minute) when each of change ratesof 3% to 7% is used as a relax-level threshold value;

FIG. 12 is a graph showing a time lag (minute) when each of change ratesof 8% to 11% is used as a relax-level threshold value;

FIG. 13 is a flow chart showing a data treatment in a standard valuederiving section;

In FIGS. 14A to 14C, FIG. 14A is a diagram showing leading edges ofnormal heartbeat signals, FIG. 14B is a diagram showing heartbeatsignals having a noise signal (misinformation), and

FIG. 14C is a diagram showing heartbeat signals with a loss of twoheartbeat signals (a loss of information);

FIG. 15 is a flow chart showing a data treatment in a firstheartbeat-signal revising section;

FIG. 16 is a flow chart showing a data treatment in a secondheartbeat-signal revising section;

FIG. 17 is a flow chart showing a supplement procedure of heartbeatsignals;

FIG 18 is a flow chart showing a procedure of revising a misinformationof a heartbeat signal and also revising a loss of heartbeat signals.

PREFERRED EMBODIMENTS OF THE INVENTION

The present invention is explained in detail referring to the attacheddrawings. FIG. 1 shows a massage chair 1 as an embodiment of a relaxinducing device of the present invention. As shown in FIG. 2, thismassage chair 1 comprises a heartbeat-number detecting unit 10 fordetecting heartbeats of a user, a massage applicator 23 of applying amassage stimulus to the user, a massage control unit 20 including amicrocomputer for controlling an action of the massage applicatoraccording to the heartbeat information provided from the detecting unit10, and a massage operation unit 30 which can be operated by the user.

The heartbeat-number detecting unit 10 is provided with a heartbeatsensor 11 and a heartbeat measuring circuit 12 of a microcomputer. Asthe heartbeat sensor 11, it is possible to use a restriction-type sensorwhich is directly loaded to a user to detect heartbeats. However, tosmoothly inducing the user into a relax state without a sensation ofpressure, it is preferred to use a non-restriction type sensor capableof detecting the heartbeats without being directly loaded to the user.As the non-restriction type sensor, it is possible to use apiezoelectric element or a capacitance-type sensor which may be arrangedon a plane of the massage chair for supporting a weight of the user, oran optical fiber which is connected at its opposite ends to a lightprojecting element and a light receiving element. In the massage chairof FIG. 1, the heartbeat number detecting unit 10 is disposed inside aseat cushion 3 of the massage chair, so that heartbeats of the usersitting on the massage chair 1 can be readily measured by the heartbeatsensor 11. The massage operating unit 30 is provided with anoperator-side control circuit 31 of a microcomputer and an operationpanel 32 available to the user.

The massage control unit 20 is incorporated in a backrest 2 of themassage chair 1. The massage applicator 23 is driven by a motor 22.Various factors for operating the massage applicator 23 can bedetermined through the operation panel 32. In the massage chair 1 ofthis embodiment, it is possible to select one massage mode from variousmassage operations of a "pushing-up massage" mode, "pushing-downmassage" mode, "tapping massage" mode, "rubbing massage mode forstraightening back", "rubbing massage mode for partially straighteningback", "complex massage mode for straightening back while tapping", and"complex massage mode for partially straightening back while tapping".As to details of these massage operations, conventional techniquesalready known in this art can be used.

A main control circuit 21 of a microcomputer included in the massagecontrol unit 20 of the massage chair 1 carries out an auto massage modewhen a user selects a "relax" course by pushing a button for the automassage mode of the operation panel 32. In the auto massage mode, amassage action of the applicator 23 is controlled according to theheartbeat information of the user output from the heartbeat-numberdetecting unit 10. Referring to FIGS. 3 to 6, a control pattern of amassage speed of the present invention is explained in detail. After thecontrol circuit 21 receives a signal indicative of the selection of the"relax" course from the operation panel 32, the massage mode forstraightening back and the massage mode for straightening back whiletapping are carried out for predetermined time periods, respectively.The massage action of the applicator 23 comes to a halt, and then aninitial massage mode is started. In this explanation, the initialmassage mode is performed for 20 seconds at a massage speed of 14times/min to determine an initial heartbeat value HR(0). The initialheartbeat value HR(0) is used as a standard value for determining arelax level of the user, and compared with a heartbeat value HR(n)subsequently measured by the heartbeat-number detecting unit 10. In thiscase, the massage speed is classified into six grades according to therelax level. That is, when ΔHR, which is presented by the followingequation:

    ΔHR={(HR(0)-HR(n)}/HR(0)}×100,

is within a range of 0% to less than 2% (1st stage), the massageapplicator 23 is driven at a first massage speed S1 (defined as anaction number (times) of the massage applicator per minute), e.g., 24times/minute. When ΔHR is within a range of 2% to less than 4% (2ndstage), the applicator is driven at a second massage speed S2 slowerthan the first massage speed, e.g., 22 times/minute. When ΔHR is withina range of 4% to less than 8% (3rd stage), the applicator is driven at athird massage speed S3 slower than the second massage speed, e.g., 20times/minute. When ΔHR is within a range of 8% to less than 11% (4thstage), the applicator is driven at a fourth massage speed S4 slowerthan the third massage speed, e.g., 18 times/minute. When ΔHR is withina range of 11% to less than 13% (5th stage), the applicator is driven ata fifth massage speed S5 slower than the second massage speed, e.g., 16times/minute. When ΔHR is within a range of 13% or more (6th stage), themassage action of the applicator is stopped.

In each of the 1st to 5th stages, the massage is applied to the user atthe respective massage speed for at least minimum time period. In thisembodiment, the minimum time period is set to 30 seconds in each of thestages. In addition, a maximum time period of massage is set to 55seconds in each of the stages. For example, when ΔHR reaches the rangeof 2% to less than 4% during the massage action of the applicator at thefirst massage speed for 30 to 55 seconds, the first massage speed ischanged to the second massage speed. By the way, when ΔHR does notsubstantially change for a predetermined time period (a predeterminedaction number (times) of the massage applicator) during the massageaction, it is preferred to slow down the present massage speed to aone-stage slower massage speed. In this embodiment, when ΔHR does notsubstantially change for 55 seconds of the maximum time period, thepresent massage speed is automatically reduced to the one-stage slowermassage speed. In addition, when ΔHR does not reach the range of 13% ormore even after 55 seconds pass from a beginning of the massage actionat the fifth massage speed S5, the massage action is automaticallystopped. Therefore, it is possible to efficiently induce the user to therelax state without interrupting the relax state such as a dozing stateof the user. As to the control pattern of this embodiment, a minimumtime period for inducing the user to the relax state, which includes thetime period for the initial massage mode, is 2 minutes and 50 seconds,as shown by the line PS of FIG. 3. On the other hand, a maximum timeperiod for inducing the user to the relax state, which includes the timeperiod for the initial massage mode, is 4 minutes and 55 seconds, asshown by the line PL of FIG. 3. As a result, the 6-stage control of themassage speed can be performed within a range surrounded with thecontrol patterns PS and PL. Although a time period necessary forinducing the user to the relax state changes in response to health andmental conditions of the user, it is normally about 3 minutes and 30seconds.

As an example, a user A was induced to a relax state along a massagespeed control pattern shown by the line PA of FIG. 3 by the use of theabove massage chair 1. That is, the user A firstly received the initialmassage for 20 seconds at the massage speed of 14 times/min to obtain aninitial heartbeat value HR(0). Subsequently, a massage was started atthe first massage speed of 24 times/min. ΔHR reached within the range of2 to less than 4% just after the elapse of 45 seconds from the beginningof the massage action at the first massage speed, so that the firstmassage speed was changed to the second massage speed. ΔHR reachedwithin the range of 4 to less than 8% just after the elapse of 35seconds from the beginning of the massage action at the second massagespeed, so that the second massage speed was changed to the third massagespeed. ΔHR reached within the range of 8 to less than 11% just after theelapse of 50 seconds from the beginning of the massage action at thethird massage speed, so that the third massage speed was changed to thefourth massage speed. In addition, ΔHR reached within the range of 11 toless than 13% just after the elapse of 35 seconds from the beginning ofthe massage action at the fourth massage speed, so that the fourthmassage speed was changed to the fifth massage speed. Finally, ΔHRreached the range of 13% or more just after the elapse of 35 secondsfrom the beginning of the massage action at the fifth massage speed, themassage action was stopped. At this time, it was confirmed that the userA reached a sleeping state which is one of relax states. In thisexample, a time period necessary for inducing the user A to the relaxstate is about 3 minutes and 40 seconds. This total time period includesthe time period for the initial massage.

Thus, it is preferred to use relax-level threshold values of 0, 2, 4, 8,11, and 13% to provide the 6-stage control of the massage speed of theapplicator. However, needless to say, it is possible to select anotherrelax-level threshold values. By the way, when the heartbeat numberincreases during a massage stage, it is preferred to keep a massagespeed of the massage stage to smoothly induce the user to the relaxlevel. In addition, if necessary, a massage action having a sixthmassage speed (S6≠0) may be given to the user when ΔHR reaches the rangeof 13% or more. In this case, the massage action of the sixth massagespeed may be stopped after being carried out for a predetermined timeperiod. In FIG. 4, a flow chart of the automatic massage mode of thepresent massage chair 1 is shown. In addition, FIGS. 5A and 5B showdetail flow charts of first and second deceleration sections shown inthe flow chart of FIG. 4, respectively.

As shown in FIG. 6, the massage speed of the massage chair 1 of thisembodiment is classified into 6 grades. Alternatively, it is possible touse a massage control system with infinitely variable speeds, as shownin FIG. 7. The number of control stages of the massage speed is notlimited to the above, although, it is preferred to classify the massagespeed into at least 3 stages. For example, in case of selecting the 3stages, it is preferred to select two relax-level threshold values froma range of 0 to less than 8% and a range of 8 to 16%, respectively.

The massage chair 1 of this embodiment uses the heartbeat-numberdetecting unit 10. Alternatively, a respiration-number detecting unitmay be used. When a massage is provided to the user at a massage cycleslightly longer than a detected respiration cycle, the respiration cyclegradually approaches to the massage cycle. As a result, since therespiration cycle moderately elongates, it is possible to smoothlyinduce the user into the relax state.

Moreover, both of the heartbeat-number detecting unit 10 and therespiration-number detecting unit may be used to the massage chair ofthe present invention, if necessary. Alternatively, it is possible touse a brain-wave detecting unit. In this case, it is preferred that anoccupation ratio of α wave is used as a control factor of the massagespeed of the massage applicator. Needless to say, the massage speed canbe controlled according to a combination of the brain-wave informationand the heartbeat information or a combination of the respirationinformation and the heartbeat information.

In place of the heartbeat-number detecting unit 10 and the controlcircuit 21 of the massage chair 1, a relax-level determining unit 40 canbe used to control the massage speed of the applicator, as shown in FIG.8. That is, the relax-level determining unit 40 comprises a heartbeatsensor 41 for sensing heartbeats of the user, aheartbeat-attainment-time measuring section 42 for providing a heartbeatattainment time, which is defined as a time period necessary to reach apredetermined heartbeat number, and measured every cycle of thepredetermined heartbeat number, a change-rate determining section 43 forproviding a change rate defined as a ratio of an initial heartbeatattainment time measured at an initial cycle of the predeterminedheartbeat number to a heartbeat attainment time measured at a subsequentcycle of the predetermined heartbeat number, and a relax-leveldetermining section 45 for determining the relax level of the user bycomparing the change rate with at least one of predetermined relax-levelthreshold values.

The heartbeat sensor used in the massage chair 1 of the FIG. 1 can beused as the heartbeat sensor 41. As an example, when the predeterminedheartbeat number is set to 20 times, the heartbeat-attainment-timemeasuring section 42 successively measures a time period necessary toreach the heartbeat number of 20 times at every cycle of the heartbeatnumber. In other words, a time period necessary to reach the heartbeatnumber of 20 times at an initial cycle, a time period necessary to reachthe heartbeat member of 20 times at the next cycle, and a time periodnecessary to reach the heartbeat member of 20 times at the cycle afternext, are successively measured by the measuring section 42. A ratio ofthe time period measured at the initial cycle to the time periodmeasured at each of the subsequent cycles is determined as the changerate of the heartbeat attainment time by the change-rate determiningsection 43. The relax-level determining section 45 determines the relaxlevel of the user by comparing the change rate output from thechange-ratio determining section 43 with the relax-level thresholdvalue. In this case, it is preferred to classify the massage speed ofthe massage applicator into three stages according to the relax level inorder to efficiently induce the user to a relax state. That is, when thechange rate is within a range of 0% to less than 4%, a massage speed ofthe applicator defined as an action number (times) of the applicator perminute is determined to a first massage speed. When the change rate iswithin a range of 4% to less than 11%, the first massage speed ischanged to a second massage speed slower than the first massage speed.When the change rate reaches a range of 11% or more, the second massagespeed is changed to a third massage speed slower than the second massagespeed. In this relax-level determining section, it is possible toaccurately determine the relax level of the user without depending oncomplex arithmetic operations such as Fourier transform.

For the following reasons, it is preferred to use the relax-levelthreshold values (4% and 11%). That is, a correlation between a relaxlevel of a user derived from a brain-wave measurement and the changerate of the heartbeat attainment time determined according to theheartbeat measurement was investigated. FIG. 9 shows a change on time ofthe relax level according to results of the brain-wave measurement. Onthe other hand, FIG. 10 shows a change on time of the change rate of theheartbeat attainment time defined as the time period necessary to reachthe heartbeat number of 20 times. An increase of the change rate (%) astime passed means that the time period necessary to reach the heartbeatnumber (20 times) gradually extends. In other words, this means that theuser is gradually approaching the relax state. As to a classification ofthe relax level of FIG. 9, when more than 50% of the brain wave is αwave and the balance is θ wave, or all of the brain wave is α wave, itdefined as a light relax level (L). When more than 50% of the brain waveis θ wave and the balance is α wave, or all of the brain wave is θ wave,it defined as a medium relax level (M). When a special wave called ashumps which can be observed at a relax state appears during themeasurement, it defined as a deep relax level (H). In FIG. 9, the relaxlevel of the user transferred from the light relax level (L) to themedium relax level (M) after the elapse of about 4 minutes from thebeginning of measurement. Subsequently, the relax level of the user alsotransferred from the medium relax level (M) to the deep relax level (H)after the elapse of about 8 minutes from the beginning of measurement.

To determine the relax level according to the change rate of theheartbeat attainment time so as to match with the results of thebrainwave measurement, each of the change rates 3, 4, 5, 6, and 7% wassupposed as a relax-level threshold value between the light relax level(L) and the medium relax level (M), and an analysis was carried out asto which change rate is suitable for the threshold value. As a result,it was confirmed that a time lag (absolute value) between a timing oftransferring from the light relax level (L) to the medium relax level(M) in the brain-wave measurement of FIG. 9 and a timing of transferringfrom a light relax level (L) to a medium relax level (M) in theheartbeat measurement is the smallest when 4% of the change rate isselected as the threshold value, as shown in FIG. 11. This means that 4%of the change rate is the most preferable to the threshold value betweenthe light relax level (L) and the medium relax level (M). Similarly,each of the change rates 8, 9, 10, 11, 12 and 13% was supposed as arelax-level threshold value between the medium relax level (M) and thedeep relax level (H), and an analysis was carried out as to which changerate is suitable for the threshold value. As a result, it was confirmedthat a time lag (absolute value) between a timing of transferring fromthe medium relax level (M) to the deep relax level (H) in the brain-wavemeasurement and a timing of transferring from a medium relax level (M)to a deep relax level (H) in the heartbeat measurement is the smallestwhen 11% of the change rate is selected as the threshold value, as shownin FIG. 12. This means that 11% of the change rate is the mostpreferable to the threshold value between the medium relax level (M) andthe deep relax level (H).

Thus, when the relax level of the user is determined from three gradesaccording to the change rate of the time period necessary to reach theheartbeat number, e.g., 20 times, at the initial cycle to the timeperiod necessary to reach the heartbeat number at the subsequent cycle,it is preferred to use 4% and 11% of the change rates as the relax-levelthreshold values. It should be understood that the change rates (4% and11%) are suitable for the relax-level threshold values when theheartbeat number in each cycle is set to 20 times, and the change rateis determined on the basis of the time period necessary to reach theheartbeat number (20 times) at the initial cycle. Therefore, therelax-level threshold values are not limited to the above thresholdvalues. In place of the above change rate, it is possible to use achange rate determined on the basis of an average value of a time periodnecessary to reach a predetermined heartbeat number at an initial cycleand a time period necessary to reach the heartbeat number at the nextcycle.

In case of providing a massage stimulus to a user by the use of amassage chair with the relax-level determining unit explained above fordetermining the relax level from the three grades, for example, it ispreferred to smoothly induce the user into a relax state that when thedetermined relax level is within a light relax level (the change rate iswithin the range of 0% to less than 4%), an massage action of theapplicator is provided to the user at a massage speed of 24 times/min,when the relax level is within a medium relax level (the change rate iswithin the range of 4% to less than 11%), the massage action is providedat a massage speed of 20 times/min, and also when the relax level iswithin a deep relax level (the change rate is within the range of 11% ormore), the massage action is provided at a massage speed of 16times/min. Since experimental data show that when the massage action isprovided at a massage speed of 26 times/min or more, it is difficult toefficiently induce the user to the relax level, it is preferred to usethe massage speed of less than 26 times/min. In addition, it is possibleto control an intensity of massage in place of changing the massagespeed. In this case, as the relax level is deeper, the massage intensitymay be reduced. Alternatively, it is preferred to simultaneously controlboth of the massage intensity and the massage speed. It is preferredthat the massage action is applied to a body portion such as a shoulderor neck to smoothly induce the user into the relax state.

As to the massage chair 1 explained above, since it is characterized inthat massage action of the applicator is controlled on a real-time basisaccording to the heartbeat signal of the user, it is needless to saythat an accurate detection of the heartbeat signal presents an massageaction adequate for a physical condition of the user. Therefore, it ispreferred to use a heartbeat-signal revising unit described below forchecking as to whether a noise signal is included in the heartbeatsignal, and revising the heartbeat signal when the noise signal isincluded.

The heartbeat-signal revising unit is provided with a standard-valuederiving section, first and second heartbeat-signal revising sections.The standard value deriving section provides a heartbeat-signal standardvalue which is defined as an average value of heartbeat-signal intervalswhen heartbeat signals having a dispersion of heartbeat-signal intervalwithin a required percentage continue for more than a predeterminednumber of times. The first heartbeat-signal revising section cancels adetected heartbeat signal when the detected heartbeat signal appears ata first interval of less than a predetermined percentage of theheartbeat-signal standard value. On the other hand, the secondheartbeat-signal revising section provides a supplemental signal when adetected heartbeat signal appears at a second interval of more than apredetermined percentage of the heartbeat-signal standard value. Thesupplement signal is inserted into the second interval. Concretely, aheartbeat change of a user detected by a heartbeat sensor is convertedto electrical signals by a detecting circuit, and further converted intodigital signals by a digitizing circuit. Subsequently, the digitalsignals are input to a microcomputer (CPU). The checking and revisingoperations of the heartbeat signals are performed in this CPU. In thefollowing explanation, a leading edge of each of the heartbeat signal isregarded as a heartbeat.

A flow chart of data treatment in the standard value deriving section isshown in FIG. 13. At the step 202, a heartbeat data is detected. At thestep 203, an interval between a leading edge (En) of a heartbeat signaland a leading edge (En-1) of an immediately previous heartbeat signal isoutput as an interval data, as shown in FIG. 14A. At the step 204, achecking operation as to whether the interval data is normal as theheartbeat interval of human is performed. That is, the step 204 is tocheck as to whether the interval data is in a range between anupper-limit value (H-limit msec) of the heartbeat interval of human anda lower-limit value (L-limit msec) of the heartbeat interval. Theupper-limit and lower-limit values can be optionally determined. Whenthe interval data is out of the range, an accumulation number of theheartbeat detection is reset to zero to wait a next interval data. Whenthe interval data is normal, in other words, the interval data is withinthe range, a checking operation as to whether a dispersion of theinterval data is within ±R % of the immediately previous interval datais performed at the step 206. The R value is a threshold value forchecking the dispersion, which is determined according to a user and acomponent of the individual relax inducing device. However, it ispreferred to select the R value from a range between 20% and 30%. At thestep 206, when the interval date is regarded as unusual, an accumulationnumber of the heartbeat detection is reset to zero to wait a nextinterval data. At the step 206, when the interval date is regarded asnormal, "1" is added to the accumulation number of the heartbeatdetection at the step 207. By repeating the above procedure from thestep 202 to the step 207, a predetermined number (n) of successive,normal interval data are stored (step 208). At the step 209, an averagevalue of those normal interval data is determined as theheartbeat-signal standard value. The number (n) of interval data is notlimited, however, it is preferred to determine the number (n) ofinterval data within a range of 3 to 10, and more preferably within arange of 4 to 6, from the viewpoint of massage efficiency and confidenceof the relax inducing device. Thus, the heartbeat-signal standard valueis determined at the standard value deriving section, and is used at thefirst and second heartbeat-signal revising sections. This standard valuederiving section can provide an accurate heartbeat-signal standard valuefor a shortened time period.

As to a misinformation including a noise (ER1) in detected heartbeatsignals, as shown in FIG. 14B, the first heartbeat-signal revisingsection revises the heartbeat signals according to the following method,as shown in FIG. 15. That is, a leading edge of each of the heartbeatsignals is detected at the step 302. At the step 303, an intervalbetween a leading edge of a heartbeat signal and a leading edge of animmediately previous heartbeat signal is determined as an interval data.At the step 304, when the interval data is less that A % of theheartbeat-signal standard value, it is regarded as unusual, and both ofthe heartbeat signal (ER1) and the immediately previous heartbeat signal(En-1) are canceled. In addition, a heartbeat signal (En-2) detectedimmediately before the heartbeat signal (En-1) is used as an immediatelyprevious heartbeat signal at the time of determining a next intervaldata (step 305). The reason for canceling both of the heartbeat signals(ER1) and (En-1) at the step 305 is explained below. The heartbeatsignal (En-1) detected immediately before the abnormal heartbeat signal(ER1) is not regarded as unusual, however, there is a possibility that asmall shift of the heartbeat interval appears in the heartbeat signal(En-1) as a sign of the unusual heartbeat signal. Therefore, theheartbeat signal (En-1) is canceled at the step 305 to improve theconfidence of the interval data. The heartbeat signal regarded as normalat the step 304 is used to control the massage action of the applicator.

When a loss of heartbeat signals occurs between heartbeat signals (En)and (En-1), as shown in FIG. 14C, the second heartbeat number revisingsection revises the heartbeat signals according to the following method,as shown in FIG. 16. That is, a leading edge of each of the heartbeatsignals is detected at the step 402. At the step 403, an intervalbetween a leading edge (En) of a heartbeat signal and a leading edge ofan immediately previous heartbeat signal is determined as an intervaldata. At the step 404, when the interval data is more than B % of theheartbeat-signal standard value, it is regarded as unusual, so that apredetermined number of heartbeat signals are supplemented between theheartbeat signals (En) and (En-1). That is, an abnormally large intervaldata, which allows to suppose that a plurality of heartbeat signals (ER2shown in FIG. 14C) are lost between the heartbeat signals (En) and(En-1), is divided by the heartbeat-signal standard value (step 502).Subsequently, the quotient of the interval data divided by the standardvalue is rounded off to obtain a first integer at the step 503. Inaddition, "1" is subtracted from the first integer at the step 504 toobtain a second integer. The second integer means the number ofsupplement heartbeat signals to be inserted between the heartbeatsignals (En) and (En-1). In FIG. 14C, the number of supplement heartbeatsignals is 2. Therefore, the supplement heartbeat signals of the numberof the second integer are inserted at a same interval within theabnormal interval data (step 505). The heartbeat signal regarded asnormal at the step 404 is used to control the massage action of theapplicator.

There is no limitation as to the threshold values A and B used in thefirst and second heartbeat-signal revising sections. However, it ispreferred that the threshold values A and B are determined within arange of 80% to 60%, and a range of 125% to 150%, respectively. In caseof providing a massage system of gradually extending the heartbeatinterval (or providing a relax state such as a sleeping state), it ispreferred to use a relatively large value within the above range as thethreshold value B, and a relatively small value within the above rangeas the threshold value A. Consequently, it is possible to performaccurate revising operations of the heartbeat signals.

FIG. 18 shows a flow chart of a heartbeat-signal revising system, inwhich revising operations for a misinformation and a loss of heartbeatsignals are continuously performed. This provides a simplification ofalgorithm and a speed-up of the revising operations.

The above-explained system performs the revising operations on areal-time basis, however, the revising operations may be performed on abatch basis, if necessary.

What is claimed is:
 1. A relax inducing device comprising:heartbeatinformation detecting means for successively measuring a heartbeatattainment time, which is defined as a time period necessary to count apredetermined heartbeat number, said heartbeat attainment time beingmeasured every cycle of the predetermined heartbeat number; change-ratedetermining means for determining a change rate which is defined as aratio of an initial heartbeat attainment time measured at an initialcycle of the predetermined heartbeat number by said heartbeatinformation detecting means to said heartbeat attainment time measuredat a subsequent cycle thereof; stimulus loading means for providing astimulus to the user; relax-level determining means for determining arelax level of the user by comparing said change rate with at least onepredetermined relax-level threshold value; and stimulus control meansfor controlling an amount of said stimulus according to said relax leveldetermined by said relax-level determining means to induce the user intoa relax state.
 2. The device as set forth in claim 1, wherein said atleast one relax-level threshold value is a plurality of relax-levelthreshold values for a multigrade evaluation of said relax level.
 3. Thedevice as set forth in claim 2, wherein said relax-level thresholdvalues are 4% and 11% of a change rate of a heartbeat attainment time,said change rate being defined as a ratio of an initial heartbeatattainment time measured at an initial cycle of a predeterminedheartbeat number to a subsequent heartbeat attainment time measured at asubsequent cycle of the predetermined heartbeat number, and saidheartbeat attainment time being defined as a time period necessary tocount the predetermined heartbeat number, and wherein said relax-leveldetermining means determines said relax level from three grades of afirst relax level within a range of less than 4% of said change rate, asecond relax level within a range of 4% to less than 11% of said changerate, and a third relax level within a range of 11% or more of saidchange rate.
 4. The device as set forth in claim 3, wherein saidstimulus control means controls said stimulus amount such that as saidrelax level increases from said first relax level toward said thirdrelax level, said stimulus amount decreases.
 5. The device as set forthin claim 2, wherein said stimulus control means controls said stimulusamount such that said stimulus loading means provides a different numberof stimulus per minute according to said relax level of the user.
 6. Thedevice as set forth in claim 2, wherein said stimulus control meanscontrols said stimulus amount such that said stimulus loading meansprovides a different strength of stimulus according to said relax levelof the user.
 7. The device as set forth in claim 2, wherein saidstimulus control means controls said stimulus amount such that saidstimulus loading means provides a different strength of stimulus at adifferent number of stimulus per minute according to said relax level ofthe user.
 8. The device as set forth in claim 1, wherein said stimulusloading means provides a kneading massage.
 9. The device as set forth inclaim 1, wherein said stimulus control means controls said stimulusamount to decrease a stimulus number of the massage actions provided bysaid stimulus loading means per minute when said said change rateprovided from said change-rate determining means is constant over apredetermined period.
 10. A relax inducing devicecomprising:heartbeat-information detecting means for successivelycounting a heartbeat number every cycle of a predetermined time period;change-rate determining means for determining a change rate (ΔHR)defined by the following equation:

    ΔHR=100X(HR(0)-HR(n))/HR(0),

wherein "HR(0)" is an initial heartbeat number counted by said heartbeatinformation detecting means at an initial cycle of the predeterminedtime period, and "HR(n)" is a heartbeat number counted at a subsequentcycle "n"(=1,2,3 . . . ); stimulus loading means for providing astimulus to the user; relax-level determining means for determining arelax level of the user by comparing said change rate provided from saidchange-rate determining means with at least one predeterminedrelax-level threshold value; and stimulus control means for controllingan amount of said stimulus according to said relax level provided fromsaid relax-level determining means to induce the user into a relaxstate.
 11. The device as set forth in claim 9, wherein said relax-levelthreshold values are 0%, 2%, 4%, 8%, 11% and 13% of said change rate ofthe heartbeat number, and said change rate being calculated by theequation defined in claim 5, and wherein said relax-level determiningmeans determines said relax level from six grades of a first relax levelwithin a range of 0% to less than 2% of said change rate, a second relaxlevel within a rage of 2% to less than 4% of said change rate, a thirdrelax level within a range of 4% to less than 8% of said change rate, afourth relax level within a range of 8% to less than 11%, a fifth relaxlevel within a range of 11% to less than 13% of said change rate, and asixth relax level within a range of 13% or more of said change rate. 12.The device as set forth in claim 11, wherein said stimulus control meanscontrols said stimulus amount such that as said relax level increasesfrom said first relax level toward said sixth relax level, said stimulusamount decreases.
 13. The device as set forth in claim 5, wherein saidat least one relax-level threshold value is a plurality of relax-levelthreshold values for a multigrade evaluation of said relax level. 14.The device as set forth in claim 5, wherein said stimulus control meanscontrols said stimulus amount such that as said heartbeat numberdecreases, said stimulus amount is smaller.
 15. The device as set forthin claim 5, further comprising:standard value deriving means forproviding a heartbeat-signal standard value which is defined as anaverage value of heartbeat-signal intervals of a predetermined number ofcontinuous heartbeat signals, said heartbeat-signal intervals having adispersion within a required percentage; and heartbeat-signal revisingmeans for canceling an abnormal heartbeat signal appeared within a firstinterval of less than a predetermined percentage of saidheartbeat-signal standard value.
 16. The device as set forth in claim 5,further comprising;standard value deriving means for providing aheartbeat-signal standard value which is defined as an average value ofheartbeat-signal intervals of a predetermined number of continuousheartbeat signals, said heartbeat-signal intervals having a dispersionwithin a required percentage; and heartbeat-signal revising means forinserting a supplement signal into a second interval of more than apredetermined percentage of said heartbeat-signal standard value. 17.The device as set forth in claim 16, wherein said heartbeat-signalrevising means providing a required number of supplement signals at aninterval substantially equal to said heartbeat-signal standard value.18. The device as set forth in claim 5, further comprising:standardvalue deriving means for providing a heartbeat-signal standard valuewhich is defined as an average value of heartbeat-signal intervals of apredetermined number of continuous heartbeat signals saidheartbeat-signal intervals having a dispersion within a requiredpercentage; and first heartbeat-signal revising means for canceling anabnormal heartbeat signal appeared within a first interval of less thana predetermined percentage of said heartbeat-signal standard value; andsecond heartbeat-signal revising means for inserting a supplement signalinto a second interval of more than a predetermined percentage of saidheartbeat-signal standard value.
 19. A relax inducing devicecomprising:heartbeat information detecting means for successivelymeasuring a heartbeat attainment time, which is defined as a time periodnecessary to count a predetermined heartbeat number, said heartbeatattainment time being measured every cycle of the predeterminedheartbeat number; a change-rate determining means for determining achange rate (ΔT) defined by the following equation:

    ΔT=100X(T(0)-T(n))/T(0),

wherein "T(0)" is an initial heartbeat attainment time measured at aninitial cycle of the predetermined heartbeat number by said heartbeatinformation detecting means, and "T(n)" is a heartbeat attainment timemeasured at a subsequent cycle "n" (=1,2,3 . . . ); stimulus loadingmeans for providing a stimulus to the user; relax-level determiningmeans for determining a relax level of the user by comparing said changerate provided from said change-rate determining means with at least onepredetermined relax-level threshold value; and stimulus control meansfor controlling an amount of stimulus according to said relax levelprovided from said relax-level determining means to induce the user intoa relax state.